There doesn't seem to be a very big contrast in text for messages you've read versus messages you still need to read. I've noticed that at least on dark mode, the white doesn't really stand out when an unread message is sitting in your box versus a read one. The fonts and text size are too similar and the bold lettering isn't as pronounced as you'd think it would be.
I anticipate the response will be something like "that's up to Google to fix." I totally agree, it's difficult to see an unread message when looking at all your chats.
As issue involves a 3rd party app, fix needs to be performed from the application side. It would be best if you let app developers know of this issue through their support channels.
